It is understood a piece of machinery fell on the man as it was being serviced. The accident happened on Monday at the JTI plant in the town. The man remains critically ill in hospital.
The man was taken to Antrim Area Hospital but later transferred to the Ulster Hospital in Belfast.
In a statement on Tuesday, the Health and Safety Executive confirmed that an investigation had begun.
“The circumstances surrounding this particular incident are under investigation and HSENI is unable to comment further at this time,” the statement said.